This document outlines ways to improve the efficiency of steam systems used in chemical plants. It defines wet and dry steam and discusses how saturated steam is commonly used in heat exchangers to utilize its high latent heat. Basic methods to enhance heat transfer are described, such as increasing temperature differences, flow rates, and heat exchange surface areas. Specific strategies are provided to optimize steam efficiency, like installing steam traps to recover condensate and insulating piping to reduce heat loss. Common problems like water hammer and stalling are also explained along with approaches to prevent them.

2. OUTLINE
 Introduction
 What is steam
 Types of steam
 Heat exchanger
 Steam in heat exchanger
 Basic ways to improve heat transfer
 Ways to improve steam efficiency
 Problems in steam equipment
 Conclusions
 References

3. INTRODUCTION
 The dramatic jump in petroleum prices over the recent
years has created much impetus to reduce operating costs
at chemical process plants.
 The plant’s steam resource is often a primary provider of
heat to a process.
 So using steam efficiently helps reducing operation cost
thereby generating savings.

4. STEAM
 Steam is the gas formed when water passes from
the liquid to the gaseous state
 Steam is one of the most common and effective
heat transfer mediums used in industry
 They are mainly used in heat exchangers,
turbines, strippers, and chemical reaction vessels

5. TYPES OF STEAM
 WET STEAM
 Wet steam applies to steam when a portion of its water
molecules have given up their energy (latent heat) and
condense to form tiny water droplets
 Also known as saturated steam
 Mixture of water in the liquid state (tiny droplets) and
gaseous state (steam)

6. DRY STEAM
Dry steam applies to steam when all its water molecules
remain in the gaseous state
Known as superheated steam
It's a transparent gas
Superheated steam and liquid water cannot coexist
under thermodynamic equilibrium

7. WET STEAM VS. DRY STEAM
WET STEAM
Rapid, even heating through latent heat transfer
High heat transfer coefficient
Originates from water
Used for heating, cooking, drying or other procedures in
industries
DRY STEAM
Low heat transfer coefficient
Temperature may be extremely high
Sensible heat used to transfer heat
Exclusively used in turbines

8. HEAT EXCHANGER
 Heat exchanger an equipment built for efficient heat transfer from
one medium to another
 The media are separated by a solid wall so that they never mix
 They are widely used in refrigeration, air conditioning, power plants,
chemical plants, petrochemical plants, petroleum refineries, and
natural gas processing
counter-current and co-current flow

9. STEAM IN HEAT EXCHANGER
Saturated steam is used in heat exchanger because it has high
heat transfer coefficient
Heat transfer with saturated steam utilizes the latent heat of
steam, releasing a large amount of energy as it condenses
Provision is made for condensate recovery

10. BASIC WAYS TO IMPROVE
HEAT TRANSFER
Temperature difference between the steam and process fluid
should be high
Using saturated steam instead of superheated steam
improves efficiency and minimizes operation cost
Higher the flow rate, higher will be the heat transfer
High conductivity of heat exchanger material helps in better
heat transfer
Larger the surface area of conducting interfaces, greater the
heat transfer rate

11. WAYS TO IMPROVE STEAM
EFFICIENCY
STEAM TRAPS
Steam traps are a type of automatic valve that filters out
condensate (condensed steam) and non-condensable gases
such as air without letting steam escape
They need to be monitored for leakage and other faults
Replacing faulty traps minimizes loss of steam and improves
efficiency

12. CONDENSATE RECOVERY
The condensate from traps can be returned to the boiler
This helps in reducing boiler fuel needs
Reducing boiler fuel needs through condensate recovery leads
to less air pollution by lowering CO2, NOx and SOx emissions
INSULATING STEAM SYSTEM
Despite high cost, insulation reduces heat loss
Helps save energy
MONITORING LEAKS
Checking the steam distribution lines and valves for leakage
and fixing them could save energy and enhance efficiency
STEAM METERING
Steam metering provides accurate steam usage statistics
It can be a useful troubleshooting tool

13. PROBLEMS IN STEAM
EQUIPMENT
WATER HAMMER (STEAM HAMMER)
Steam first supplied to steam distribution piping or steam-
using equipment, a metallic and repetitive 'bang, bang, bang',
or even sometimes a violent 'boom' accompanied by vibration
may be heard
Caused by high levels of accumulated condensate inside the
equipment

14. Water hammer causes a momentary abrupt pressure change
of over 10MPa inside the piping
Can severely damage piping and equipment

15. FIXING IT
Rapid discharge of condensate is critical from a preventative
maintenance standpoint
The speed of condensate discharge combined with how
smoothly the process occurs are two extremely important
factors in the fight against water hammer in steam-using
equipment
Proper design and orientation of the equipment

16. STALL
Occurs when the necessary pressure differential across a
drainage device such as a trap becomes negative
Condensate is no longer discharged from the drainage device
and instead pools inside the heat exchanger
Linked to the following problems - ruptured heaters, water
hammer, uneven heating temperatures

17. FIXING IT
Increasing trap inlet (primary) pressure
Reducing trap outlet (secondary) pressure

18. CONCLUSIONS
By proper use of steam, operational cost can be minimized
and high efficiency is achieved
Condensate recovery and recycling back to boiler helps
reducing boiler fuel needs thereby minimizing pollution
Damage to equipment can be averted by properly regulating
the steam
Using steam intelligently lowers carbon emission

19. REFERENCES
http://www.tlv.com/global/SG/steam-theory
James R. Risko, optimize the Entire Steam System, CEP June
2008, 31-32
James R. Risko, Understanding Steam Traps, CEP Feb 2011, 21-
26
James R. Risko, Handle Steam More Intelligently, CHEMICAL
ENGINEERING www.che.com Nov 2006, 44-48